In which case must a COMSEC custodian's approval be obtained?

A COMSEC (Communications Security) custodian's approval must be obtained for all transmissions of COMSEC information because they are responsible for safeguarding classified and sensitive information as well as ensuring compliance with regulatory requirements. This approval is crucial to prevent unauthorized access and to maintain the integrity and confidentiality of the information being transmitted.

In the context of the DoD, COMSEC custodians adhere to strict protocols for the handling and dissemination of cryptographic materials and secure communications. Their oversight helps to mitigate risks associated with the transmission of sensitive data, regardless of the classification or form of communication. Thus, acquiring the custodian's approval is a fundamental step in maintaining information security and operational effectiveness.

Other scenarios, such as unclassified transmissions, internal communications, or personal information, do not universally require COMSEC custodian approval. They may not involve sensitive or secured information or may fall outside the purview of COMSEC regulations, thus making the requirement for custodian approval less relevant in those contexts.